Page:Cyclopaedia, Chambers - Supplement, Volume 2.djvu/329

 PYR

ore with fix centners of the black flux, and two of fandiver, and finifh the work in the common way, only making the fire stealer, and continuing it longer, toward the end of the operation. Cramer** Art of allaying, p. 292. See the article

PYRITlCtJM liqwmitl. SecLlCiyAMEUfyriticum.

PYRITRICHIPHYLLUM, in natural hiftory, the name of a genus of fulfils of the clafs of the pyritae, the character* of which are theft": they are compound, inflammable, metallic bodies found in lool'e maffes not of any regularly angular fi- E ure and of a (Mated texture, with fohaceous ends to the irriae', appearing on the furface or within the mafs. See Tab. of Foff. Clafs ;°

Of this genus there are only two known fpecies ; one having the fohaceous ends of the ftrix on the outer furface of the mafs and the other having a fmooth external furface, and the fohaceous ends of the ftriae covering the fides of internal hol- lows. Hilts Hid. of Foff. p. 617.

The firft is a foflil of great beauty, of a very firm texture, remarkably heavy, and ufually found in large maffes of an or- bicular or oblong figure : theft maffes are fometimes compofed wholly of the matter of the pyrites, and in others they are only coats of that fubftance furrounding ftones. It is of a very clofely ftriated texture, and the ftria; are broad, but unequally fo, and their extremities at the furface of the mafs are beautifully formed into feveral feries of thin foha- ceous plates, which ufually cover all the fuperficies, and ftand up to "feveral heighths and in different angles, but moftly leaning one way ; they are of unequal thickneffes, being com- pofed of different numbers of plates, and are ufually notched at the ends. The whole is of a fomewhat deep green, with a cad of olive or amber colour, and when it is frefh broken, is very bright and glittering.

The fecond is a foflil of equal beauty with the former, tho' of a very different appearance ; it is very hard and very heavy, and is always found in detached maffes ; but thofe of a very lingular kind, for they are always more or lefs hollow. Thefe maffes are of various figures and appearances, fometimes round and like pebbles, but more frequently full of odd protube- rances, like the flints in our chalk pits; and fometimes the maffes of it are found running over the furfaces of ftones in form of crufts, which are varioufly protuberant in different parts, and rife into frequent beautiful tho' irregular tubercles. The outer furface of this fpecies is ufually very bright and gloffy, and perfectly fmooth, as if wrought by art, even on the tubercles themfelves. It is ufually a fort of cruft even in its moft folid mafles, feldom being above half an inch thick, and of a very beautifully ftriated texture, the ftria: being re- markably fine and (lender. Thefe, tho' they unite fo at their fuperficies as to form a very fmooth furface, yet at their other ends, where they terminate at the hollows of the maffes, are expanded into very elegant feries of fohaceous plates, ufually approaching to a fqjare figure, and not (landing erect, as in the other fpecies, but King horizontally and almoft perfectly flat over one another : thefe are compofed of flakes not thicker than thofe of many of the foliacious talcs. The whole is ufually of a gold yellow, and very blight and beautiful ; but the outer furface often contracts a dull brownifh hue on being long expofed to the air.

The firft of thefe is found in many of the Englifh and Ger- man mines, the other has been yet only found in the mines on Mendip hills in Somerfetfhire, but there in confiderable plenty. Hill's Hid. of Foff p. 618.

PYRITRICHUM, in natural hiftory, the name of a genus of pyritie, the characters of which are thefe : they are com- pound, inflammable, metallic foflils, always found indetached maffes of no regularly angular figure, and of a (imply ftriated internal ftruaure. See Tab. of Foff. Clafs 5. Of this genus of pyritae there are three known fpecies, 1. A globofe one, with an irregular furface. 2. A globofe one covered with angular tubercles. 3. A filver-coloured globofe one, with a fmooth furface.

The firft is considerably hard, and very remarkably heavy, and is ufually of a roundifh form, tho' fometimes oblong fometimes it is full of irregular prominences on the furface, and fometimes is a complex mafs, confiding of a great number of roundifh maffes of fmoother or rougher furfaces joined to gether. It is very various in fize ; the more common fpeci mens of it are of fix or eight ounces weight, tho' there are others of lefs than an ounce, and fome of feveral pounds. The prominences on the furface are ufually broad and dc- prefled, and thefe are frequently marked with irregular (hort lines, and raifed in ridges. When broken, it is found to be of a very regular ftriated ftruflure ; the driae are not very broad, and ufually run from the center to the circumference. It is of a pale whitifh green within, and is covered with a brown or ferrugineous crud.

The fecond is a very firm and hard body, ufually of an orb: cular figure, and fometimes, tho' rarely, oblong; it is of a very remarkably rough furface, being covered with pyramidal tubercles, with veryobtufe ends. Thefe are of a quadrangu- lar figure, and have very broad bafes : they fometimes incline, pr bend a little ; but more ufually they ftand perfectly upright, and are placed fo clofe together, that they croud and injure

PYR

one another's figure at their bafes. The whole is of a ferru- gineous or ruft colour without, and of a yellowifh colour within, beautifully ftriated, and very bright and glittering. The third is an extremely elegant and beautiful fpecies, it is but moderately hard, tho' remarkably heavy, and is ufually of a regularly orbicular form, tho' fometimes it varies from it like the other pyritae. Its moft frequent fize is about an inch and half in diameter; but it is fometimes found as (mail as a nut, or a fchoolboy's marble, and fometimes of more than two pounds weight. Its furface is ufually fmooth and even, and it is never covered with any coat or crud. It is of a very regularly driated internal druflure, and of a beau- tiful filvery green colour: the ftria: are moderately broad and run very evenly from the center to the circumference ; and very often there is a fma.ll and firm central nucleus, which is much harder than the reft of the mafs, and is of a plain not ftriated ftrudture.

All the three fpecies are found plentifully in different parts of the kingdom : the firft in all forts of ftrata, and often loofs on the ground; the fecond, principally in the chalk pits of Kent and Stiffex ; and the laft in Effex and Hampfhirc, and very frequently in the German mines. Hill's Hift. of Foff p. 6 1 7. PYRMONT-tuflrcrr. The country all about where thefe fprings are, abound with materials which give virtue to the waters; and the quarries of done, wherever they are dug, fend up fpirituous and martial exhalations as well as the fprings that run from them, and the water among them has in general a vitriolic tafte. Iron is found all about the place alfo, under the appearance of a yellowifh earth or ochre, which contains fo much of that metal, that it may be worked as an ore of it to great advantage. Ferrugineous ftones are alfo found in great abundance in the neighbourhood of the place ; thefe may be alfo worked as iron ores, and the felenites is found in the drata of earth that make up the hills there- about, in great abundance, and in beautiful perfection. The waters themfelves, tho' they (hew evident marks of an alkali, yet have alfo an acid principle in them, of the nature of the common acid of fulphur, except in this, that in thefe waters the acid carries with it a fubtle mineral oil or fattinef.; and mixing with the common alkali fait, which is found in all mineral waters, thefe together form a neutral fait : but as in the compofition of this fait there is much more alkali than acid, it is neceflary that the water (hould (hew alkaline ra- ther than acid qualities. The analyfis (hews alfo, that the waters contain a flony matter embodied in them, which is pure, infipid, colourlefs and tafielefs, and feems to be in no- thing different from common cryftal. The earth about the fprings contains alfo a great number of lumps of a clayey mat- ter, of the fize of a walnut, and of a yellowifh colour ; in all of which, when broken, there is found pure crydal in fmall (hoots, fometimes in its own regular figure, and fome- times irregular and mutilated.

A water containing thefe principles thus combined, cannot but poffefs thofe virtues we find fo eminent in this ; thefe are, the opening obftruifions, correfling the (harpnefs of the hu- mors, and reftoring the folids to their due date. Scipf, Nova Defcrip. Font. Pyrm.

The hidory of thefe wat«rs is accurately given by Hoffman in his obfervations on them, both in their natural date and in mixture with other bodies.

He fird obferves, that they contain a volatile and fubtle prin- ciple,^ greatly more penetrating and drong, as well as in larger quantity, than any other mineral water; but that this is not to be expected in them any where but upon the fpot, for thofe who tranfport them to other places are condrained to let a part of this fly off to preferve the red. If either glafs or earthen veffels be filled at the fpring, and immediately corked and fattened down, the confequence is, that they will burft on the firft motion or heat of the weather. They are, there- fore, forced to fill them only in part at firft, and let them ftand a while for this fubtle fpirit to exhale, and then a while after the filling them up, to cork and fit them for carriage.

2. If they are drank upon the fpot in a morning on an empty ftomach, they affect the nofe with a pungent tingling, and didurb the head for many hours afterwards.

3. If they are taken at the fpring, they purge but very little ; but if taken in another place, after tranfportation, they purge confiderahly more, and render the dools black. It is obferv- able alfo, that if they are left in an open veffel a few days, their virtue wholly exhales, and they no longer purge nor ren- der the dools black.

4. If tea-leaves, balauftine-flowers, or galls, are put into this water, they firft change it to a blue, from that to a purple, and finally to a black. This is a ready proof, that black is only a deep purple, and purple only a deep blue : a little fpirit of vitriol added to this liquor deftroys all ihe colour, and renders it limpid as before.

5. If any acid be mixed with Pyrnant vxit.r, there is raifed an effervefcence, and bubbles of air are carried up in great quantity ; and this whether the ftronger acids, fuch as fpirit of vitriol, or aqua fortis, be ufed ; or the weaker, as vinegar, lemon-juice, or Rhenifh wine.

6. If an alkaline liquor be added, whether it be volatile, as the fpirit of fal armoniac ; or fixed, as the oil of tartar, there